In vitro induction of SCE in human lymphocytes by epichlorohydrin with and without metabolic activation

Human lymphocytes cultured for 73 h in the presence of BrdU were exposed to epichlorohydrin (ECH) with and without metabolic activation. Cells exposed for the entire culture time without activation showed a significant dose related increase in SCE yield. Exposure for the final 25 h only showed a similar response but with increased tolerance. The presence of S9 mix significantly reduced the effect of ECH compared with a similar exposure without activation. Without activation 4 X 10(-4) M ECH produced a 3-fold increase in the incidence of SCE over the control level. However, with S9 mix a concentration of 10(-3) M ECH was required to produce such an increase indicating that S9 mix may have a detoxifying effect.